Hydrogenation process

ABSTRACT

ACCORDING TO THE INVENTION THERE IS PROVIDED A HIGHLY ACTIVATED PROCESS FOT THE HYDROGENATION OF CYCLOPENTADIENE TO CYCLOPENTENE BY BRINGING THE CYCLOPENTADIENE INTO CONTACT WITH A CATALYST COMPRISING (1) NICKEL ON A METAL OXALATE, SAID METAL BEING SELECTED FROM THE GROUPS CONSISTING OF MAGNESIUM AND ZINC, (2) AT LEAST ONE LIGAND SELECTED FROM THE GROUP CONSISTING OF PHOSPHINES AND PHOSPHITES WHILE IN THE PRESENCE OF HYDROGEN AT TEMPERATURES FROM ABOUT 0*C. TO ABOUT 200*C. AND HYDROGEN PRESSURE RANGING FROM ABOUT 0 TO ABOUT 10,000 POUNDS PER SQUARE INCH GAUGE (P.S.I.G.).

United States Patent 3,819,734 HYDROGENATION PROCESS Vipin M. Kothari,Akron, and James J. Tazuma, Stow,

Ohio, assignors to The Goodyear Tire & Rubber Company, Akron, Ohio NoDrawing. Filed May 5, 1972, Ser. No. 250,801 Int. Cl. C07c 5/06 US. Cl.260-666 A 7 Claims ABSTRACT OF THE DISCLOSURE According to the inventionthere is provided a highly activated process for the hydrogenation ofcyclopentadione to cyclopentene by bringing the cyclopentadiene intocontact with a catalyst comprising (1) nickel on a metal oxalate, saidmetal being selected from the groups consisting of magnesium and zinc,(2) at least one ligand selected from the group consisting of phosphinesand phosphites while in the presence of hydrogen at temperatures fromabout 0 C. to about 200 C. and hydrogen pressure ranging from about 0 toabout 10,000 pounds per square inch gauge (p.s.i.g.).

This invention is directed to a method of hydrogenation of hydrocarbons.

It is also directed to the discovery of a highly active hydrogenationcatalyst. More specifically, this invention relates to a catalyst and aprocess useful for the selective hydrogenation of cyclopentadiene tocyclopentene.

The selective hydrogenation of unsaturated hydrocarbons to monoolefinsand parafiin with a supported catalyst is well known in the prior art.The hydrogenation of unsaturated hydrocarbons with mixed oxalates andformates, i.e. nickel and magnesium or zinc oxalates (or formates) hasalso been reported.

In this invention, however, the active nickel/magnesiumoxalate catalystis prepared and used with a ligand. This catalyst when used with theadded ligand results in an activated catalyst which is far more activethan the previously reported catalysts without any ligands.

Therefore, according to the invention there is provided a highlyactivated process for the hydrogenation of cyclopentadiene tocyclopentene by bringing the cyclopentadiene into contact with acatalyst comprising (1) nickel, on a metal oxalate, said metal beingselected from the groups consisting of magnesium and zinc and (2) atleast one ligand selected from the group consisting of phosphines andphosphites, while in the presence of hydrogen, at temperatures fromabout 0 C. to about 200 C. and hydrogen pressure ranging from about 0 toabout 10,000 pounds per square inch gauge (p.s.i.g.).

The componentof this invention which comprises the nickel on metaloxalate is comprised of nickel oxalates decomposed on supports such asmagnesium and zinc oxalates. This useful component is obtained bypreparing a mixed nickel oxalate/magnesium or zinc oxalate andreductively decomposing the nickel oxalate so that the nickel metal isdeposited on the magnesium or zinc oxalate. A typical but not limitingmethod of reductively decomposing the mixed nickel oxalate/magnesium orzinc oxalate is by heating the mixture in a hydrogen atmosphere at about200 C. to about 350 C. from about 1 to about 4 hours. Thenickel/magnesium or zinc oxalate formed upon decomposition is a blackpyrophoric powder and contains magnesium or zinc oxalate which functionsas a support.

The catalyst formation may be illustrated by the following equation:

ice

The mixed nickel/magnesium or zinc oxalate was prepared by mixing andstirring together aqueous solutions of nickel salts, magnesium or zincsalts and oxalic acid. The amounts of the reactants may be varied togive different percentages of nickel and magnesium or zinc in themixture.

The mole ratio of nickel oxalate/magnesium or zinc oxalate can rangefrom about .1/ 1 to about 9/1. The preferred mole ratio is from about.25/1 to about 1.5/1.

The preferred range of the nickel metal is therefore from about 20 toabout 60 mole percent by weight of the catalyst. Specific amounts of thesalts and concentrations cannot be set forth since factors such aspurity, difierent starting salts which may be utilized and the desiredpercent of each ingredient may be varied.

The combined use of the catalyst and the ligand in this invention, givesthe high selectivity to the desired product.

The molar ratio of ligand/ Ni that can be used in this invention canrange from about 1/1 to about 5/1 based on the amount of nickel in thereductively decomposed catalyst. The preferred molar ratio is from about1.5/1 to about 2.5/1.

The component of the catalyst used in this invention which greatlyenhances the overall activity of the catalytic system and helps to makea new type of catalyst are compounds which contain an atom or radicalwhich is capable of leading or sharing electrons with the nickel metalused in this invention. Such compounds may be called ligands. Ligand isdefined as an ion or molecule bound to and considered bonded to a metalatom or ion. Mono-dentate means having one position through whichcovalent or coordinate bonds with the metal may be formed; bi-dentatemeans having two positions through which covalent or coordinate bondswith the metal may be formed.

Compounds which are capable of functioning as useful ligands in thisinvention are phosphines and phosphites.

The phosphine subclass can be defined by the formula where R, R and R"may represent alkyl, cycloalkyl, aryl, alkaryl and arylalkyl radicalscontaining from about 1 to about 10 carbon atoms; R, R' and R may be thesame or dissimilar. These phosphines represent a class of compoundswhich have three carbon atoms attached by single bonds to phosphorusatom. Representative but not exhaustive of the phosphines useful asligands in this invention are trimethyl, tributyl phosphines ortriphenyl phosphine, methyl diethyl phosphine, methyl ethyl propylphosphine or methyl ethyl phenyl phosphine, methyl diphenyl phosphine,phenyl dimethyl phosphine, cyclohexyl methyl butyl phosphine, diisobutyltolyl phosphine and the like.

The phosphite subclass can be defined by the formula where R, R and Rrepresent alkyl, cycloalkyl, aryl, alkaryl, and arylalkyl radicalscontaining from about 1 to about 10 carbon atoms; R, R and R may be thesame or dissimilar. These phosphites represent a class of compoundswhich have three carbon atoms attached to three oxygen atoms by singlebonds and the oxygen atoms attached by single bonds to a phosphorousatom. Representative but not exhaustive of the phosphites useful asligands in this invention are trimethyl phosphite, triethyl phosphite,tributyl phosphite, triphenyl phosphite, methyl ethyl propyl phosphite,methyl ethyl phenyl phosphite and dimethyl phenyl phosphite, methylethyl phosphite, diethyl phenyl phosphite and diphenyl ethyl phosphite.

3 4 Although the hydrogenation examples were carried out diene tocyclopentene by bringing said cyclopentadiene batchwise in theseexamples, it should be understood that into contact with a catalystconsisting essentially of (1) the hydrogenation reaction may be carriedout continuousnickel, on a metal oxalate support, said metal being selyover a fixed bed or in a fluid bed. The hydrogenation lected from thegroup consisting of magnesium and zinc,

may be carried out with or without a solvent. If a solvent 5 and (2) aligand selected from the group consisting of triis used it should be onethat will not undergo reduction. methyl phosphine, methyl diethylphosphine, methyl ethyl The temperature range used for the hydrogenationreacpropyl phosphine, trimethyl phosphite, triethyl phospite, tion maybe from about 0 C. to about 200 C. The pretributyl posphite, triphenylphosphite, methyl ethyl propyl ferred range is from about 20 C. to about100 C. The phosphite, methyl ethyl phenyl phosphite, dimethylphenpressure under which the hydrogenation reaction may be yl phosphite,tributyl phosphine, triphenyl phosphine, conducted can be from aboutzero pounds square inch methyl ethyl phenyl phosphine, while in thepresence of gauge *(p.s.i.g.) to about 10,000 pounds square inch gaugehydrogen, at temperatures from about 0 C. and pressures (p.s.i.g.).However, it may be advantageous to conduct from atmospheric to about1000 pounds pressure per the hydrogenation in the range of atmosphericpressure square inch gauge (p.s.i.g.). to about 1000 pounds per squareinch gauge (p.s.i.g.). 2. A process according to Claim 1 in which thenickel Further practice of this invention is illustrated byrefconstitutes from about 10 molar percent to about 90 erence to thefollowing examples which are intended to be molar percent by weight ofthe component (1) of the catillustrative and in no manner limiting.alyst.

3. A process according to Claim 2 in which the pre- EXAMPLE I ferredamount of nickel ranges from about 20 molar percent to about 60 molarercent b wei ht of the com o- The cyclopentadiene (10 grams) was mlxedwith 40- mm (1) f the catalyst p y g p milliliters of ethanol in a 500milliliter Parr hydrogena- A process according to Claim 1 in which theligand tion bottle. One-tenth (0.1) gram of nickel/magnesium ofcomponent (2) is selected from the group consisting oxalate and 0.86gram tributyl phosphite, (BuO) P, were 25 of phosphines and phosphitesadded to the ethanol solution. The bottle is then closed 5 A o t 1 h h 1and allowed to rock and heat at 135 F. in the hydrogenapr F accor mg 0mm W t 6 mo 6 tion equipmgnt under hydrogen pressure of 55 60 poundsratio of the ligand of component (2)/nickel of component per square inchgauge (p.s.i.g.) until a desired drop in (1) ranges from about V toabout the hydrogen pressure is achieved. The time for reaction 30 Aprocesfaccordlng to (3181111 5 In which the prewas 4045 i Th ll of hcyclopentadiene was ferred mole ratio of the llgand of component(2)/nickel hydrogenated with percent going to cyclopentene and ofComponent ranges from about 1-5/1 t ab ut 10 percent going tocyclopentane. 2.5/1.

TABLE 1 CPD COHV. 0f CPD Ni/Mg-ox. Time, Temp., CPD to Run (gms.) weightratio Solvent Ligand min. F. products Products I 1 10 EtOH (BuOhP, .86gm. 40-45 135 100 {90% OPE 10% CPA 5 10 100 EtOH (Ph)aP, .89 gm. 13598.4 {88% CPE 12% CPA o 10 100 (Ph) P .89 gm. 130 135 100 857 on O-Mo a{15% CPA I CPD Cyclopentadiene.

9 ox. Oxalate.

' Ligandlnickel=2l1 (molar ratio).

4 CPE =Cyelopentene; CPA=Cyclopentane.'

EXAMPLE II 50 7. A process for selectively hydrogenating cyclopentadieneto cyclopentene by bringing said cyclopentadiene into This example isthe same as Example I except that the contact with a catalyst consistingessentially of (1) nickel, ligand was not used. It can be noted that theconversion on a metal oxalate support, said metal being selected from ofthe hydrocarbon is much lower than with the ligand. the group consistingof magnesium and zinc, and (2) a TABLE 2 CPD Conv. oi CPD Ni/Mg-ox. TimeTemp. CPDto Run (gms.) weight ratio Solvent (min.) F.) products ProductsI 10 100 EtOH 120 4 100% OPE 10 50 EtOH 120 20 100% OPE 10 15 EtOH 12040 100% OPE 1 GPD=Cyclopentadiene. I ox.=oxalate. CPE=Oyclopentene.

While certain representative embodiments and details ligand selectedfrom the group consisting of trimethyl have been shown for the purposeof illustrating the inphosphine, tributyl phosphine, triphenylphosphine, methvention, it will be apparent to those skilled in this arttha 70 yl ethyl propyl phosphine, methyl diphenyl phosphine, variouschanges and modifications may be made therein phenyl dimethyl phosphine,cyclohexyl methyl butyl phoswithout departing from the spirit or scopeof the invenphine, diisobutyl tolyl phosphine, trimethyl phosphite,trition. butyl phosphite, triphenyl phosphite, methyl ethyl phos- Whatis claimed is: phite, methyl ethyl phenyl phosphite, diethyl phenylphos- 1. A process for selectively hydrogenating cyclopenta- 75 phiteand diphenyl ethyl phosphite, while in the presence 5 6 of hydrogen, attemperatures from about 0 C. and pres- 3,041,385 6/1962 Bourne 260677 Hsures from atmospheric to about 1000 pounds pressure 3,274,282 9/1966Bourne 260677 H per square inch gauge (p.s.i.g.). 3,472,763 10/1969Cosyns 260-677 H References Cited 5 VERONICA OKEEFE, Primary ExaminerUNITED STATES PATENTS US. Cl- XR. 3,110,747 11/1963 Mullineaux 260677 H3,004,914 10/1961 White 260677 H 252431CP;26677H

